| Abstract: | Wind energy has emerged as a major sustainable source of energy.The efficiency of wind power generation by wind mills has improved a lot during the last three decades.There is still further scope for maximising the conversion of wind energy into mechanical energy.In this context,the wind turbine rotor dynamics has great significance.The present work aims at a comprehensive study of the Horizontal Axis Wind Turbine (HAWT) aerodynamics by numerically solving the fluid dynamic equations with the help of a finite-volume Navier-Stokes CFD solver.As a more general goal,the study aims at providing the capabilities of modern numerical techniques for the complex fluid dynamic problems of HAWT.The main purpose is hence to maximize the physics of power extraction by wind turbines.This research demonstrates the potential of an incompressible Navier-Stokes CFD method for the aerodynamic power performance analysis of horizontal axis wind turbine.The National Renewable Energy Laboratory USA-NREL (Technical Report NREL/Cp-500-28589) had carried out an experimental work aimed at the real time performance prediction of horizontal axis wind turbine.In addition to a comparison between the results reported by NREL made and CFD simulations,comparisons are made for the local flow angle at several stations ahead of the wind turbine blades.The comparison has shown that fairly good predictions can be made for pressure distribution and torque.Subsequently, the wind-field effects on the blade aerodynamics,as well as the blade/tower interaction,were investigated.The selected case corresponded to a 12.5 m/s up-wind HAWT at zero degree of yaw angle and a rotational speed of 25 rpm.The results obtained suggest that the present can cope well with the flows encountered around wind turbines.The areodynamic performance of the turbine and the flow details near and off the turbine blades and tower can be analysed using theses results.The aerodynamic performance of airfoils differs from one another.The performance mainly depends on co-efficient of performnace,co-efficient of lift,co-efficient of drag, velocity of fluid and angle of attack.This study shows that the velocity is not constant for all angles of attack of different airfoils.The performance parameters are calculated analytically and are compared with the standardized performance tests.For different angles of ,the velocity stall is determined for the better performance of a system with respect to velocity.The research addresses the effect of surface roughness factor on the blade surface at various sections.The numerical results were found to be in agreement with the experimental data.A relative advantage of the theoretical aerofoil design method is that it allows many different concepts to be explored economically.Such efforts are generally impractical in wind tunnels because of time and money constraints.Thus, the need for a theoretical aerofoil design method is threefold:first for the design of aerofoil that fall outside the range of applicability of existing calalogs:second,for the design of aerofoil that more exactly match the requirements of the intended application:and third,for the economic exploration of many aerofoil concepts.From the results obtained for the different aerofoils,the velocity is not constant for all angles of attack.The results obtained for the aerofoil mainly depend on angle of attack and velocity.The vortex generator technique was meticulously studies with the formulation of the specification for the right angle shaped vortex generators-VG.The results were validated in accordance with the primary analysis phase.The results were found to be in good agreement with the power curve.The introduction of correct size VGs at appropriate locations over the blades of the selected HAWT was found to increase the power generation by about 4% |
| Description: | Division of Safety and Fire Engineering,School of Engineering,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2946 |
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| Dyuthi-T0937.pdf | (13.63Mb) |
| Abstract: | In Statistical Machine Translation from English to Malayalam, an unseen English sentence is translated into its equivalent Malayalam translation using statistical models like translation model, language model and a decoder. A parallel corpus of English-Malayalam is used in the training phase. Word to word alignments has to be set up among the sentence pairs of the source and target language before subjecting them for training. This paper is deals with the techniques which can be adopted for improving the alignment model of SMT. Incorporating the parts of speech information into the bilingual corpus has eliminated many of the insignificant alignments. Also identifying the name entities and cognates present in the sentence pairs has proved to be advantageous while setting up the alignments. Moreover, reduction of the unwanted alignments has brought in better training results. Experiments conducted on a sample corpus have generated reasonably good Malayalam translations and the results are verified with F measure, BLEU and WER evaluation metrics |
| URI: | http://dyuthi.cusat.ac.in/purl/4187 |
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| Techniques to I ... m English to Malayalam.pdf | (368.5Kb) |
| Description: | Department of Applied Economics, Cochin University of Science And Technology. |
| URI: | http://dyuthi.cusat.ac.in/purl/3001 |
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| Dyuthi-T0981.pdf | (2.602Mb) |
| Abstract: | Induction of growth in the primary marine fishing industry of Kerala is a sine gua Qgn for improving the economy of the fishermen, the state's domestic product as well as earning more foreign exchange for the country. The State Administration has been trying to instil growth into the industry eversince the output of the industry showed marked sign of decline (particularly after 1975). Significantly, it has attempted to strengthen the traditional sector, (which is considered to be the crucial sector of the primary marine fishing industry of the state) by introducing intermediate technology and by revamping the organisational structure of the industry. But it appears that the production system in the primary marine fishing industry of Kerala has been severely constrained by the existing technology, organisation of production and marketing institutions. Regeneration of growth in the industry calls forth an understanding of the 'process' of growth in the industry and the need to réorganise it with new technology, and new organisations. The present study is an attempt to unraval the process of growth in the primary marine fishing industry of Kerala since 1951 |
| Description: | Department of Applied Economics Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3724 |
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| Dyuthi-T1692.pdf | (7.633Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1334 |
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| Ramakrishnan Korakandy 1988.PDF | (728.5Kb) |
| Abstract: | The present study describes in detail the major technological advances in the rubber-growing industry in the lastfour decades. The major technological changes experienced in the rubber plantation industry during the period are the introduction of 'high yielding-planting materials, scientific application of fertilisers, use of pesticides, tapping during rainy season using‘rain guards, use of. yield stimulants and improved tapping methods School of Management Studies, Cochin University of Science and Technology |
| Description: | School of Management Studies, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3441 |
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| Dyuthi-T1237.pdf | (3.881Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1608 |
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| Dyuthi-T0296.pdf | (4.292Mb) |
| Abstract: | Curing is the oldest and cheapest method of preservation of fish allover the world. Fish curing industry has not shown much improverrent from its primitive nature because this industry is mainly handled by illiterate and less educated fishermen/fisherwomen. They do not know much about,the importance of scientific methods of fish curing. The cured fish produced by them is unhygienic and poor in quality. Because of the negligenence and ignorance of the fish curers, a considerable quanti ty of this protein rich food is spoiled and lost every year. Research has been conducted extensively in the Cen tral and State sectors and various remedial measures have been suggested :to improve the fish curing industry in India. Inspi te of the preJudioa against cured fish because of their existing low quality, research work in recent years have indicated that their quality can be greaUy improved and shelf-life prolonged if the me thods are standardised. To achieve this aim, Cen tral and s tate Departments have already made considerable efforts to transfer the improved methods ~ the fish curing industry by way of traininq courses, demonstrations, Lab, to Land Prograrrmesi film shows, exhibitions, personal discussion etc. As the result of this, fish curers have started adopting the improved practices in fish curing. Still there seems to be a considerable qap between the techmology available and the technology adopted in this field. A comprehensive study on the extent of adoption of improved practices in fish curing and the factors involved in low or non-adoption of certain aspects is lackin~ at present. This gap has to be filled up. The possihle methods for the effective transfer of technology for the production and distribution of high quali ty cured fish products and improvement of soclo-economic condition of fishermen engaqed in fish curing have to be identified. |
| Description: | School of marine sciences, Central institute of fisheries technology, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3457 |
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| Dyuthi-T1467.pdf | (6.817Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5131 |
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| Sept-Oct2015_18.pdf | (1.396Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5129 |
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| Jan-Feb2016_19.pdf | (1.861Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5132 |
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| Jan-Feb2016_19.pdf | (1.861Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5130 |
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| May-June2015_16.pdf | (9.136Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5133 |
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| May-June2015_16.pdf | (9.136Mb) |
| Abstract: | Polarized Raman spectral changes with respect to temperature were investigated for Pr(BrO3)3·9H2O single crystals. FTIR spectra of hydrated and deuterated analogues were also recorded and analysed. Temperature dependent Raman spectral variation have been explained with the help of the thermograms recorded for the crystal. Factor group analysis could propose the appearance ofBrO3 ions at sites corresponding to C3v (4) and D3h (2). Analysis of the vibrational bands at room temperature confirms a distorted C3v symmetry for the BrO3 ion in the crystal. From the vibrations of water molecules, hydrogen bonds of varying strengths have also been identified in the crystal. The appearance υ1 mode of BrO3− anion at lower wavenumber region is attributed to the attachment of hydrogen atoms to the BrO3− anion. At high temperatures, structural rearrangement is taking place for bothH2Omolecule and BrO3 ions leading to the loss ofwater molecules and structural reorientation of bromate ions causing phase transition of the crystal at the temperature of 447 K. |
| Description: | Spectrochimica Acta Part A 64 (2006) 518–525 |
| URI: | http://dyuthi.cusat.ac.in/purl/4557 |
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| Temperature dep ... id (Pr) single crystal.pdf | (184.5Kb) |
| Abstract: | The microwave dielectric properties of ZnAl2O4 spinels were investigated and their properties were tailored by adding different mole fractions of Ti02. The samples were synthesized using the mixed oxide rout.e. The phase purity and crystal structure were identified using X-ray diffraction technique. The sintered specimens were characterized in the microwave frequency range (3-13 GHz). The ZnA12O4 ceramics exhibited interesting dielectric properties (dielectric constant (e,.) = 8.5, unloaded quality factor (Q.) = 4590 at 12.27 GHz and temperature coefficient of resonant frequency (Tf) = -79 ppm/°C). Addition of Ti02 into the spinel improved its properties and the Tf approached zero for 0.83ZnAl2O4- 0.17TiO2• This temperature compensated composition has excellent microwave dielectric properties (Cr _ 12.67, Q, = 9950 at 10.075 GHz) which can be exploited for microwave substrate applications |
| URI: | http://dyuthi.cusat.ac.in/purl/1492 |
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| Temperature sta ... substrate applications.PDF | (3.226Mb) |
| Description: | Department of Physics, Cochin University of Science & Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2551 |
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| Dyuthi-T0695.pdf | (11.98Mb) |
| Abstract: | Potential applications of nickel nanoparticles demand the synthesis of self-protected nickel nanoparticles by different synthesis techniques. A novel and simple technique for the synthesis of self-protected nickel nanoparticles is realized by the inter-matrix synthesis of nickel nanoparticles by cation exchange reduction in two types of resins. Two different polymer templates namely strongly acidic cation exchange resins and weakly acidic cation exchange resins provided with cation exchange sites which can anchor metal cations by the ion exchange process are used. The nickel ions which are held at the cation exchange sites by ion fixation can be subsequently reduced to metal nanoparticles by using sodium borohydride as the reducing agent. The composites are cycled repeating the loading reduction cycle involved in the synthesis procedure. X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron microscopy, Energy Dispersive Spectrum, and Inductively Coupled Plasma Analysis are effectively utilized to investigate the different structural characteristics of the nanocomposites. The hysteresis loop parameters namely saturation magnetization and coercivity are measured using Vibrating Sample Magnetometer. The thermomagnetization study is also conducted to evaluate the Curie temperature values of the composites. The effect of cycling on the structural and magnetic characteristics of the two composites are dealt in detail. A comparison between the different characteristics of the two nanocomposites is also provided |
| Description: | Nanoscale Res Lett (2010) 5:889–897 |
| URI: | http://dyuthi.cusat.ac.in/purl/4390 |
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| Template-Assist ... edNickel Nanoparticles.pdf | (815.2Kb) |
| Abstract: | Spectroscopic studies of laser -induced plasma from a high-temperature superconducting material, viz., YBa2Cu3O7 (YBCO), have been carried out. Electron temperature and electron density measurements were made from spectral data. The Stark broad ening of emission lines was used to determine the electron density, and the ratio of line in tensities was exploited for the determination of electron temperature. An initial electron temperature of 2.35 eV and electron density of 2.5 3 1017 cm2 3 were observed. The dependence on electron temperature and density on different experimental parameters such as distance from the target, delay time after the in itiation of the plasm a, and laser irradiance is also discussed in detail. Index Headings: Laser -plasma spectroscopy; Plasma diagnostics; Emission spectroscop y; YBa2Cu3O7. |
| URI: | http://dyuthi.cusat.ac.in/purl/2384 |
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| Dyuthi-P0205.pdf | (207.7Kb) |
| Abstract: | Laser ablation of graphite has been carried out using 1.06mm radiation from a Q-switched Nd:YAG laser and the time of flight distribution of molecular C2 present in the resultant plasma is investigated in terms of distance from the target as well as laser fluences employing time resolved spectroscopic technique. At low laser fluences the intensities of the emission lines from C2 exhibit only single peak structure while beyond a threshold laser fluence, emission from C2 shows a twin peak distribution in time. The occurrence of the faster velocity component at higher laser fluences is explained as due to species generated from recombination processes while the delayed peak is attributed to dissociation of higher carbon clusters resulting in the generation of C2 molecule. Analysis of measured data provides a fairly complete picture of the evolution and dynamics of C2 species in the laser induced plasma from graphite. |
| URI: | http://dyuthi.cusat.ac.in/purl/2452 |
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| Dyuthi-P0313.pdf | (113.0Kb) |
| Abstract: | YBa2Cu307 target was laser ablated, and the time-of-flight (TOF) distributions of Y, Y+., and YO in the resultant plasma were investigated as functions of distance from the target and laser energy density using emission spectroscopy. Up to a short distance from the target (-1.5 cm), TOF distributions show twin peaks for Y and YO, while only single-peak distribution is observed for Y+. At greater distances (>1.5 cm) all of them exhibit single-peak distribution. The twin peaks are assigned to species corresponding to those generated directly/m the vicinity of target surface and to those generated from collisional/recombination process. |
| URI: | http://dyuthi.cusat.ac.in/purl/2447 |
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| Dyuthi-P0308.pdf | (970.6Kb) |
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